The source-level JSON-serializability invariant was only a preflight: the Session constructor copied the seed array but shared every event/data object with the caller, and append() stored the caller's `data` reference verbatim. A post-create/post-append mutation could rewrite the durable log or reintroduce a non-JSON-serializable value AFTER validation, so session.events could diverge from what was validated / what a backend can persist. - ctor deep-clones each seed event after validation (not just the array). - append() stores structuredClone(data) (serializability already checked, so the clone is safe); the returned event carries the same snapshot. Regression tests: mutating the original seed / the passed append object after the call leaves session.events unchanged. Adapted the dev-freeze invariants test to assert on the logged clone (append no longer freezes the caller's input). Documented isJsonValue's exact scope (own enumerable string keys, matching JSON.stringify) and synced the README create() signature with meta.createdAt.
Packages
Harness packages, all under the @deepseek-ai/dsh-* scope. Each package is a Cordis service (microkernel plugin-style): it exports a default Service class that gets registered via ctx.plugin(), declares its ctx key and events through declaration merging, and exposes extension points through ctx.effect(), ctx.on(), and ctx.waterfall().
Dependency graph
dsh-llm (no harness deps — pure vocabulary)
dsh-bash (no harness deps — abstract executor seam)
dsh-session ← dsh-llm
dsh-system-prompt ← dsh-llm
dsh-agent ← dsh-llm, dsh-session
dsh-tools ← dsh-llm, dsh-system-prompt, dsh-agent
dsh-bash-local ← dsh-bash (BashExecutor impl)
dsh-tool-bash ← dsh-bash, dsh-tools (bash tool schemas)
dsh-llm-deepseek ← dsh-llm (DeepSeek adapter)
dsh-llm-pi-ai ← dsh-llm (pi-ai-backed adapter)
dsh-agent-loop ← dsh-llm, dsh-session, dsh-system-prompt, dsh-tools, dsh-agent
dsh-invariants ← dsh-llm, dsh-session, dsh-agent (dev-mode contract checks)
The rule: plugins depend on interfaces, never on the concrete loop. dsh-agent-loop is swappable — UI/hook/tool plugins keep working against the dsh-agent vocabulary if the loop is replaced. A swappable capability splits into interface / implementation / consumer packages (the bash trio is the template — see ADR 0009).
What goes where
| Package | Role | ctx key |
|---|---|---|
llm/ |
Abstract LLM service + content-block vocabulary + chunk assembler | ctx.llm |
session/ |
Event-sourced session log + in-memory store | ctx.sessions |
system-prompt/ |
Prompt-section + tool-schema assembly registry | ctx.systemPrompt |
tools/ |
Tool registry + tools/execute waterfall |
ctx.tools |
agent/ |
Agent interface, registry, agent/* event vocabulary |
ctx.agents |
agent-loop/ |
THE concrete plugin: LoopAgent + the loop driver |
ctx.agentLoop |
bash/ |
Abstract bash executor seam (interface + vocabulary) | ctx.bash |
bash-local/ |
Local-subprocess BashExecutor implementation |
(registers ctx.bash) |
tool-bash/ |
Model-facing bash/bash_output/bash_kill tool schemas |
(registers on ctx.tools) |
llm-deepseek/ |
DeepSeek API adapter (hand-rolled fetch/SSE) | (registers on ctx.llm) |
llm-pi-ai/ |
DeepSeek adapter via @earendil-works/pi-ai (design twin) |
(registers on ctx.llm) |
invariants/ |
Dev-mode event-contract invariants + session-log freeze | (listens on session/*, agent/*) |
Each package has its own README.md with purpose, service API, events, extension points, and deliberate non-goals (TODOs).
Conventions (applied across all harness packages)
- Registrations are effects: every contribution (adapter, tool, section, agent, event listener) goes through
ctx.effect()/ctx.on(), so disposal and HMR clean up automatically. Everyregister()returns the disposer. - Declaration merging for events and ctx: services declare their events in
declare module 'cordis' { interface Events { ... } }and their ctx key ininterface Context. - Waterfall semantics:
ctx.waterfalllisteners receive(...args, next)and MUST callnext()to delegate; returning without it short-circuits (the veto mechanism). - Extensible unions:
ContentBlockMap,MessageSourceMap,FinishReasonMap,TurnTriggerMap,TurnEndReasonMap, andSessionEventMapuse the merge-extensible-map pattern so plugins can add variants via declaration merging. - ESM everywhere; imports use package names across package boundaries,
.tsextensions within a package. - Tests: vitest, colocated under
packages/<name>/tests/*.spec.ts. Every registry needs an HMR-safety test. Err on the side of more tests.